66401958 has 48 divisors (see below), whose sum is σ = 156838464. Its totient is φ = 18683280.

The previous prime is 66401957. The next prime is 66402043. The reversal of 66401958 is 85910466.

It is a hoax number, since the sum of its digits (39) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66401957) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 18013 + ... + 21383.

It is an arithmetic number, because the mean of its divisors is an integer number (3267468).

Almost surely, 2^66401958 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66401958, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (78419232).

66401958 is an abundant number, since it is smaller than the sum of its proper divisors (90436506).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66401958 is a wasteful number, since it uses less digits than its factorization.

66401958 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3457 (or 3450 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 39.

The square root of 66401958 is about 8148.7396571494. The cubic root of 66401958 is about 404.9427506336.

The spelling of 66401958 in words is "sixty-six million, four hundred one thousand, nine hundred fifty-eight".